I'm 23, and had a desk job for the last 5 years. Being so busy, I've found that I almost always go out to eat. In the last 5 years, I've put on 60lbs (bringing me from 135 to 195lbs.), and recently had a good scare, I ended up going to the doctor and having a bunch of tests done, because they thought I had a heart attack. I was having really sharp pains in the upper left part of my chest and I couldn't breath, after going to and from the hospital several times, they can not find a cause. So anyway, I'm now trying to get back into shape. I've been watching what I eat a lot more, and I joined a gym.

I'm really worried about working too hard since I've done very little to exercise in the last few years. Every time I go, I start with free weights, for half an hour or so, then I move to the Cardio room, and get on a machine in there. It has the ability to set how long you want to work out, your age weight etc. I try to go for 10-15 minutes at a time, my concern though, is that after about 2 minutes, it starts beeping and tells me that I've reached my desired heart rate of 175. I keep going, but keep an eye on it, one time I've had it get just over 200. After a long story (sorry) I guess my questions are, am I working too hard to start? Should I stop when my heart rate gets to a certain point (what is the limit)?

Thanks for your help!

Absolutely stop when you have reached the maximum heart rate.

As for your chest pain, well, it may not have been a heart attack, because it would have been radiating pain, tightness in the throat, pain to your arms, that is a heart attack.

How about your blood pressure, cholesterol, etc. are they within normal ranges ?

With all the times I had to go to the doctor for them to do tests on my heart, there was only one time they told me I had high blood pressure, every other time they said it was normal. I have never had my cholesterol or anything checked.

What would be the maximum heart rate? The machine I work out on just says I've reached the desired heart rate.

Thanks for the reply!